A conventional refrigerating cabinet or freezing cabinet obtains required cold energy from a refrigeration-cycle device, so as to cool or freeze foods or vegetables and fruits stored or displayed therein. The refrigeration-cycle device for the refrigerating cabinet or freezing cabinet includes a compressor, a condenser, an expansion valve and an evaporator, through which a coolant sequentially passes to circulate in the refrigeration-cycle device. The condenser releases heat energy while the evaporator produces cold energy, and the produced cold energy is supplied to the refrigerating cabinet or freezing cabinet for keeping an interior thereof at required low temperatures. The conventional refrigerating cabinet or freezing cabinet obtains the cold energy completely from the evaporator, and the cold energy is delivered to the interior of the refrigerating cabinet or freezing cabinet via air passages provided inside the refrigerating cabinet or freezing cabinet.
The conventional refrigerating cabinet or freezing cabinet may be a refrigerator or a refrigerated showcase. The refrigerated showcase may be an open refrigerated showcase or a closed refrigerated showcase, and the latter is openably closed by, for example, glass doors. The refrigerated showcases have been widely used in supermarkets and hypermarkets to hold and display foods to be sold. The refrigerated showcases not only function to keep the foods displayed therein in a fresh and hydrated state, but also effectively display the foods to be sold in an eye-catching manner to attract more consumers to buy them.